The principal study within this project concerns the transient kinetics of the sodium pump. A collaboration with J. Froehlich of NIA is directed at determining the extent to which oligomeric interactions of the sodium pump contribute to the efficiency of cation transport. We have obtained evidence, by a variety of techniques, that out-of-phase interactions of two or more alpha subunits occur in the native state of this and other P-type cation pumps. In addition, R. Wayne Albers is collaborating with P. Sharma and N. Amin of the LNC in studies of the mechanism of the cdk5 kinase reaction and the kinetics of the interaction of this kinase with its activator. - Na,K-ATPase sodium pump transient kinetics oligomeric interactions